y the suggestion of a friend that some other roost must have
been broken up and its members turned into the Melrose gathering. But on
the evening of the 28th I tried a count by myself, and made only 1517
birds! The conditions were favorable, and the robins came, as they had
come the night before, in flocks, almost in continuous streams. The
figures had fallen off, not because there were fewer birds, but because
I was unable to count them. They were literally too many for me. The
difficulties of the work, it should be explained, are greatly enhanced
by the fact that at the very corner where the influx is largest none of
the low-flying birds can be seen except for a second or two, as they
dart across a bit of sky between the roost and an outlying wood. To
secure anything like a complete census, this point must be watched
continuously; and meantime birds are streaming in at the other corner
and shooting over the distracted enumerator's head, and perhaps dropping
out of the sky. I conclude, therefore, not that the roost had increased
in population, but that my last year's reckoning was even more
inadequate than I then supposed. Even with two pairs of eyes, it is
inevitable that multitudes of birds should pass in unnoticed, especially
during the latter half of the flight. I have never had an assistant or a
looker-on to whom this was not perfectly apparent.

As I stood night after night watching the robins stream into this little
wood,--no better, surely, than many they had passed on their way,--I
asked myself again and again what could be the motive that drew them
together. The flocking of birds for a long journey, or in the winter
season, is less mysterious. In times of danger and distress there is no
doubt a feeling of safety in a crowd. But robins cannot be afraid of the
dark. Why, then, should not each sleep upon its own feeding grounds,
alone, or with a few neighbors for company, instead of flying two or
three miles, more or less, twice a day, simply for the sake of passing
the night in a general roost?

Such questions we must perhaps be content to ask without expecting an
answer. By nature the robin is strongly gregarious, and though his
present mode of existence does not permit him to live during the summer
in close communities,--as marsh wrens do, for example, and some of our
swallows,--his ancestral passion for society still asserts itself at
nightfall. Ten or twelve years ago, when I was bird-gazing in Boston,
the